我在显示城市的下拉列表时遇到问题。 我正在使用自动完成TextView显示下拉列表。 该应用程序的工作方式如下：
city_picker.setText设置为空字符串
因为我不希望用户选择不在该省内的城市。代码：
public class MainActivity extends AppCompatActivity {
private AutoCompleteTextView province_picker, city_picker;
public static final String TAG = "Locationdemo";
private ArrayList<String> province = new ArrayList<>();
private ArrayList<String> city = new ArrayList<>();
private ArrayAdapter<String> province_adapter, city_adapter;
private String province_code;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
city_picker = findViewById(R.id.city_picker);
city_adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, city);
city_picker.setAdapter(city_adapter);
city_picker.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View arg0) {
city_picker.showDropDown();
getCurrentFocus().clearFocus();
}
});
city_picker.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
city_picker.setError(null, null);
}
});
province_picker = findViewById(R.id.province_picker);
province_adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, province);
province_picker.setAdapter(province_adapter);
province_picker.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View arg0) {
getProvince();
province_picker.showDropDown();
getCurrentFocus().clearFocus();
}
});
province_picker.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
city_picker.setText("");
String item_selected = (String) parent.getItemAtPosition(position);
province_picker.setError(null, null);
getProvinceCode(item_selected);
getCity();
//Log.i(TAG, item_selected);
}
});
}
/**
public void nextButton(View view) {
String province = province_picker.getText().toString();
String city = city_picker.getText().toString();
if (validateInputs(province, city)) {
}
}
private boolean validateInputs(String province, String city) {
if (province.equals("")) {
province_picker.setError("Required");
}
if (city.equals("")) {
city_picker.setError("Required");
}
return true;
}
**/
public void getCity() {
city.clear();
String city_json;
try {
InputStream input_stream = getAssets().open("city.json");
int size = input_stream.available();
byte[] buffer = new byte[size];
input_stream.read(buffer);
input_stream.close();
city_json = new String(buffer, "UTF-8");
JSONArray json_array = new JSONArray(city_json);
for (int i = 0; i < json_array.length(); i++) {
JSONObject json_object = json_array.getJSONObject(i);
if (json_object.getString("provCode").equals(province_code)) {
city.add(json_object.getString("citymunDesc"));
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
Log.i(TAG, city.toString());
Log.i(TAG, "City Length: " + city.size());
city_adapter.getFilter().filter(null);
city_adapter.notifyDataSetChanged();
}
public void getProvinceCode(String province) {
String province_json;
try {
InputStream input_stream = getAssets().open("province.json");
int size = input_stream.available();
byte[] buffer = new byte[size];
input_stream.read(buffer);
input_stream.close();
province_json = new String(buffer, "UTF-8");
JSONArray json_array = new JSONArray(province_json);
for (int i = 0; i < json_array.length(); i++) {
JSONObject json_object = json_array.getJSONObject(i);
if (json_object.getString("provDesc").equals(province)) {
province_code = json_object.getString("provCode");
}
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
//Log.i(TAG, province_code);
}
public void getProvince() {
//Log.i(TAG, "getProvince()");
//Log.i(TAG, "Province: " + province.toString());
province.clear();
String province_json;
try {
InputStream input_stream = getAssets().open("province.json");
int size = input_stream.available();
byte[] buffer = new byte[size];
input_stream.read(buffer);
input_stream.close();
province_json = new String(buffer, "UTF-8");
JSONArray json_array = new JSONArray(province_json);
for (int i = 0; i < json_array.length(); i++) {
JSONObject json_object = json_array.getJSONObject(i);
province.add(json_object.getString("provDesc"));
}
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
//Log.i(TAG, province.toString());
//Log.i(TAG, "Province Length: " + province.size());
}
}
布局资源文件
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="true"
android:focusableInTouchMode="true"
tools:context=".MainActivity">
<android.support.design.widget.TextInputLayout
android:id="@+id/province_input_layout"
style="@style/TextInputLayoutStyle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:hint="@string/province"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<AutoCompleteTextView
android:id="@+id/province_picker"
style="@style/AutoCompleteTextViewStyle.Picker"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:id="@+id/city_input_layout"
style="@style/TextInputLayoutStyle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"
android:hint="@string/city"
app:layout_constraintEnd_toEndOf="@+id/province_input_layout"
app:layout_constraintStart_toStartOf="@+id/province_input_layout"
app:layout_constraintTop_toBottomOf="@+id/province_input_layout">
<AutoCompleteTextView
android:id="@+id/city_picker"
style="@style/AutoCompleteTextViewStyle.Picker"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</android.support.design.widget.TextInputLayout>
<Button
android:id="@+id/next_button"
style="@style/ButtonStyle.Light"
android:layout_height="wrap_content"
android:layout_marginEnd="32dp"
android:layout_marginStart="32dp"
android:layout_marginTop="32dp"
android:onClick="nextButton"
android:text="@string/next"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/city_input_layout" />
</android.support.constraint.ConstraintLayout>